Mobile devices can be used for wireless communication and various computing tasks. For example, use of mobile devices with wireless connectivity such laptops, tablets, smart mobile phones and so on is well established. Wireless communications can be provided between mobile user devices and access points such as base stations, servers, machine type devices and so on. Communications can also be provided between mobile devices.
Data transmissions between parties may need to be secured. Various applications for example banking, shopping, email and so on, may rely on secure transactions over the Internet, other networks or interfaces open to attacks. Increase in Internet commerce and transfer of computing tasks to remote servers (e.g. “cloud computing”) has emphasized the need to maintain appropriate security of communications. Security can be provided based on a cryptographic protocol. Current cryptographic schemes (e.g. public key encryption) rely on the hardness of solving certain mathematical problems. For example, the commonly used RSA encryption algorithm is based on the hardness of factoring a large number into its prime factors. This is a hard problem using standard computer technology but can become solvable with development of more powerful computing technologies, for example by a future quantum computer, Hence new technologies for securing communications are being studied. One possible solution is based on quantum mechanics and more particularly quantum key distribution (QKD).
In the context of mobile communications an issue may arise in that the mobile devices are often handheld or otherwise portable or can otherwise move during communications. Thus, although the other party may be fixed the location and/or position of the mobile device might not be known, and may change during communications.
It is noted that the above discussed issues are not limited to any particular communication environments and apparatus but may occur in any context where security is needed for communications where at least one party is anyhow moving.
Embodiments of the invention aim to address one or several of issues when quantum cryptography is applied to mobile devices,